Converts JSON to a CSV string. Only works with a one-dimensional JavaScript array of one-dimensional objects.

json-to-csv.js

// Convert JSON to a CSV string
function jsonToCsv(json) {
  const replaceEmpty = (key, value) => {
    return value === null ? '' : value;
  };
  const parseRow = row => {
    return header.map(fieldName =>
      JSON.stringify(row[fieldName], replaceEmpty)
    ).join(',');
  };
  const header = Object.keys(json[0]);
  const rows = json.map(parseRow);
  const rowsWithHeader = [header.join(','), ...rows];
  const csv = rowsWithHeader.join('\r\n');
  
  return csv;
}